Nowadays, electrical and electronic industries continuously develop power converters that require high efficiency, high power density and high reliability. High efficiency indicates low power consumption, low pollution generation, environment friendliness and low use cost. High power density indicates small volume, light weightiness, low transportation cost, small layout space and low installation cost. High reliability indicates long use life and low maintenance cost. As know, a semiconductor component is one of the important factors influencing the efficiency of the power converter. For complying with the requirements of the power converter, the general trends in designing semiconductor components are toward small size, compact package, light weightiness and portability. For example, more and more semiconductor components such as driving components, monitoring components and passive components have to be placed within a package structure. As the size of the package structure of the power component is gradually reduced, the demand on high heat-dissipating efficiency is gradually increased.
Generally, a power converter comprises at least one power component and a driving circuit for driving the at least one power component. The driving circuit comprises a driving component and passive components (e.g., capacitors or resistors). In a conventional power converter, a direct bonded copper (DBC) substrate is usually used as an installation carrier of the power component, and the DBC substrate and the power component are collaboratively encapsulated as a package structure. In addition, the driving circuit is located outside the package structure.
Moreover, with the increasing development of electronic industries, the internal circuitries of the electronic devices are gradually modularized to increase the power density. For example, by packaging the driving circuit and the power component as a package structure, the driving circuit and the power component of the power converter are integrated into a single circuit module. Since the signal or voltage that is transmitted or received by the driving circuit is lower, the demand on the current-flowing capability (i.e., the current-withstanding capability) of the driving circuit is not high. In other words, the trace of the driving circuit can be made denser. However, due to the characteristics of the direct bonded copper substrate, the traces of the direct bonded copper substrate are neither narrow nor dense. For example, the minimum width of the trace for the 0.25 mm-thickness direct bonded copper substrate is 0.5 mm. Consequently, the direct bonded copper substrate in the conventional package structure of the power converter is only used to install the power component that requires current-flowing capability and the heat-dissipating efficiency. In other words, the direct bonded copper substrate is not suitable for installing the driving circuit. Consequently, the power density of the conventional package structure of the power converter is still not satisfied.
As mentioned above, an additional component or means is required to integrate the driving circuit into the package structure that contains the direct bonded copper substrate. Under this circumstance, the size and the wiring flexibility of the package structure of the power converter are limited.
Therefore, there is a need of providing a package structure with enhanced heat-dissipating efficiency and a fabricating method thereof so as to overcome the above drawbacks.